ST. PETERSBURG, June 6 -- The argument that Russia has been diplomatically isolated since its military operation in Ukraine began arrived in St. Petersburg this week only to be refuted by the room it walked into. That was the assessment, at least, of Fernand Kartheiser, a member of the European Parliament from Luxembourg, who stood on the sidelines of the St. Petersburg International Economic Forum and offered a verdict that most of his colleagues in Brussels would not dare deliver aloud.

"The political and diplomatic isolation of Russia is a failure," Kartheiser told RIA Novosti on the forum's sidelines. "You can see that the whole world has gathered here in St. Petersburg."

The remark was brief. Its weight, however, came from where it...